Q: pop ups after upgrading to Yosemite

I had the same problem and just called apple support and within 10 minutes they were all gone! The support I got was free.

Back up all data before proceeding.

Launch the Keychain Access application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Select the login keychain from the list on the left side of the Keychain Access window. If your default keychain has a different name, select that.

If the lock icon in the top left corner of the window shows that the keychain is locked, click to unlock it. You'll be prompted for the keychain password, which is the same as your login password, unless you've changed it.

Right-click or control-click the login entry in the list. From the menu that pops up, select

          Change Settings for Keychain "login"

In the sheet that opens, uncheck both boxes, if not already unchecked.

From the menu bar, select

          Keychain Access ▹ Preferences... ▹ First Aid

There are four checkboxes in the window that opens. Check all of them. if they're not already checked. Close the window.

Select

          Keychain Access ▹ Keychain First Aid

from the menu bar and repair the keychain. Quit Keychain Access.

If you use iCloud Keychain, open the iCloud preference pane and uncheck the Keychain box. You'll be prompted to delete the local iCloud keychain. Confirm. Then re-check the box. Follow one of the procedures described in this support article to set up iCloud Keychain on an additional device.

What is the exact, complete wording of the alerts?

There are several possible causes for this issue. Please take each of the following steps that you haven't already tried, testing after each one, until it's resolved. Back up all data before making any changes.

Step 1

Follow the directions in this support article.

Step 2

Launch the Keychain Access application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Select the iCloud keychain from the list on the left side of the Keychain Access window. If your default keychain has a different name, select that.

If the lock icon in the top left corner of the window shows that the keychain is locked, click to unlock it. You'll be prompted for the keychain password, which is the same as your login password.

Select

          Keychain Access ▹ Keychain First Aid

from the menu bar and repair the keychain.

Step 3

Open the iCloud preference pane and uncheck the Keychain box. You'll be prompted to delete the local iCloud keychain. Confirm. Then re-check the box. Follow one of the procedures described in this support article to set up iCloud Keychain on an additional device.

Step 4

Open the Keychains folder as in Step 1. There should be a file in that folder with the name "login.keychain". If there is also a file iwith the name "login_renamed_1.keychain", then please do as follows:

☞ Rename login.keychain to "login-old.keychain".

☞ Rename login_renamed_1.keychain to "login.keychain".

You can then close the folder. 

Delete the login keychain from the keychain list in Keychain Access. Choose

           Delete References

when prompted, not Delete References & Files.

Select

          File ▹ Add Keychain...

from the menu bar. Add back the file now named "login.keychain". If any of your needed keychain items are missing from it, also add back the file now named "login-old.keychain". I suggest you transfer any needed items from that keychain to the login keychain, then delete it. The transfers are made by drag-and-drop in Keychain Access. You'll need to enter your password for each item transferred. 

Run Keychain First Aid again. Quit Keychain Access.